Method and apparatus for dermatological treatment and tissue reshaping

ABSTRACT

The present invention provides improved methods and apparatus for skin treatment and tissue remodeling. The apparatus includes an array of needles that penetrate the skin and serve as electrodes to deliver radio frequency current or other electrical or optical energy into the tissue being treated, causing thermal damage in controlled patterns. The damaged regions promote beneficial results such as uniform skin tightening by stimulation of wound healing and collagen growth.

RELATED APPLICATION

The present application is a continuation of U.S. patent applicationSer. No. 12/914,201 filed on Oct. 28, 2010, which is a divisional ofU.S. patent application Ser. No. 11/098,030 filed on Apr. 1, 2005, nowU.S. Pat. No. 7,824,394, issued on Nov. 2, 2010, which claims benefit toU.S. Provisional Application No. 60/558,476 filed on Apr. 1, 2004. Theentire disclosures of such applications are incorporated herein byreference.

INCORPORATION BY REFERENCE

The foregoing applications, and all documents cited therein or duringtheir prosecution (“appln cited documents”) and all documents cited orreferenced in the appln cited documents, and all documents cited orreferenced herein (“herein cited documents”), and all documents cited orreferenced in herein cited documents, together with any manufacturer'sinstructions, descriptions, product specifications, and product sheetsfor any products mentioned herein or in any document incorporated byreference herein, are hereby incorporated herein by reference, and maybe employed in the practice of the invention.

FIELD OF THE INVENTION

The present invention is directed to an improved method for treatment ofskin and other tissues. More specifically, it is directed to a method offractional wounding using arrays of needles to damage selected regionsof the skin or subdermal tissue and thereby promote beneficial resultsincluding skin tightening and tissue remodeling.

BACKGROUND OF THE INVENTION

Skin is primarily made of two layers. The outer layer, or epidermis, hasa depth of approximately 100 μm. The inner layer, or dermis, has depthof approximately 3000 μm from the outer surface of the skin and isprimarily composed of a network of fibrous protein known as collagen.

There is an increasing demand for repair of skin defects, which can beinduced by aging, sun exposure, dermatological diseases, traumaticeffects, and the like. Aging skin tends to lose its elasticity, leadingto increased formation of wrinkles and sagging. Other causes ofundesirable wrinkles in skin include excessive weight loss andpregnancy. There are several well-known surgical approaches to improvingthe appearance of skin that involve incisions being made in the skinfollowed by the removal of some tissue and rejoining of the remainingtissue. These surgical approaches include facelifts, brow lifts, breastlifts, and “tummy tucks.” Such approaches have many negative sideeffects including scar formation, long healing times, displacement ofskin from its original location relative to the underlying bonestructure, and nonuniform skin tightening.

Many treatments have been developed that use electromagnetic radiationto improve skin defects by inducing a thermal injury to the skin, whichresults in a complex wound healing response of the skin. This leads to abiological repair of the injured skin and may be accompanied by otherdesirable effects. Various techniques providing this objective have beenintroduced in recent years. The different techniques can be generallycategorized in two groups of treatment modalities: ablative laser skinresurfacing (“LSR”) and non-ablative collagen remodeling (“NCR”). Thefirst group of treatment modalities, LSR, includes causing fairlyextensive thermal damage to the epidermis and/or dermis, while thesecond group, NCR, is designed to avoid thermal damage of the epidermis.

LSR is considered to be an effective laser treatment for repairing skin.In a typical LSR procedure, shown schematically in FIG. 1, a region ofthe epidermis 100 and a corresponding region of the dermis 110 beneathit are thermally damaged to promote wound healing. Electromagneticenergy 120 is directed towards a region of skin, ablating the skin andremoving both epidermal and dermal tissue in region 130. LSR with pulsedCO₂ or Er:YAG lasers, which may be referred to in the art as laserresurfacing or ablative resurfacing, is considered to be an effectivetreatment option for signs of photo aged skin, chronically aged skin,scars, superficial pigmented lesions, stretch marks, and superficialskin lesions. However, patients may experience major drawbacks aftereach LSR treatment, including edema, oozing, and burning discomfortduring first fourteen (14) days after treatment. These major drawbackscan be unacceptable for many patients. A further problem with LSRprocedures is that the procedures are relatively painful and thereforegenerally require an application of a significant amount of analgesia.While LSR of relatively small areas can be performed under localanesthesia provided by injection of an anestheticum, LSR of relativelylarge areas is frequently performed under general anesthesia or afternerve blockade by multiple injections of anesthetic.

A limitation of LSR is that ablative resurfacing in areas other than theface generally have a greater risk of scarring because the recovery fromskin injury within these areas is not very effective. Further, LSRtechniques are better suited for correction of pigmentation defects andsmall lesions than for reducing or eliminating wrinkles.

In an attempt to overcome the problems associated with LSR procedures,several types of NCR techniques has emerged. These techniques arevariously referred to in the art as non-ablative resurfacing,non-ablative subsurfacing, or non-ablative skin remodeling. NCRtechniques generally utilize non-ablative lasers, flashlamps, or radiofrequency current to damage dermal tissue while sparing damage to theepidermal tissue. The concept behind NCR techniques is that thermaldamage of the dermal tissue is thought to induce collagen shrinkage,leading to tightening of the skin above, and stimulation of woundhealing which results in biological repair and formation of new dermalcollagen. This type of wound healing can result in a decrease ofstructural damage related to photoaging. Avoidance of epidermal damagein NCR techniques decreases the severity and duration oftreatment-related side effects. In particular, post-procedural oozing,crusting, pigmentary changes and incidence of infections due toprolonged loss of the epidermal barrier function can usually be avoidedby using NCR techniques.

In the NCR method of skin treatment, illustrated schematically in FIG.2, selective portions of dermal tissue 135 within the dermal layer 110are heated to induce wound healing without damaging the epidermis 100above. Selective dermal damage that leaves the epidermis undamaged canbe achieved by cooling the surface of the skin and focusingelectromagnetic energy 120, which may be a laser beam, onto dermalregion 135 using lens 125. Other strategies are also applied usingnonablative lasers to achieve damage to the dermis while sparing theepidermis in NCR treatment methods. Nonablative lasers used in NCRprocedures generally have a deeper dermal penetration depth as comparedto ablative lasers used in LSR procedures. Wavelengths in the nearinfrared spectrum can be used. These wavelengths cause the non-ablativelaser to have a deeper penetration depth than the verysuperficially-absorbed ablative Er:YAG and CO₂ lasers. Examples of NCRtechniques and apparatus are disclosed by Anderson et al. in U.S. PatentPublication No. 2002/0161357.

While it has been demonstrated that these NCR techniques can assist inavoiding epidermal damage, one of the major drawbacks of thesetechniques is their limited efficacies. The improvement of photoagedskin or scars after the treatment with NCR techniques is significantlysmaller than the improvements found when LSR ablative techniques areutilized. Even after multiple treatments, the clinical improvement isoften far below the patient's expectations. In addition, clinicalimprovement is usually several months delayed after a series oftreatment procedures. NCR is moderately effective for wrinkle removaland is generally not effective for dyschromia. One advantage of NCR isthat it does not have the undesirable side effects that arecharacteristic of the LSR treatment, such as the risk of scarring orinfection.

Another limitation of NCR procedures relates to the breadth ofacceptable treatment parameters for safe and effective treatment ofdermatological disorders. The NCR procedures generally rely on anoptimum coordination of laser energy and cooling parameters, which canresult in art unwanted temperature profile within the skin leading toeither no therapeutic effect or scar formation due to the overheating ofa relatively large volume of the tissue.

Another approach to skin tightening and wrinkle removal involves theapplication of radio frequency (“RF”) electrical current to dermaltissue via a cooled electrode at the surface of the skin. Application ofRF current in this noninvasive manner results in a heated regiondeveloped below the electrode that damages a relatively large volume ofthe dermis, and epidermal damage is minimized by the active cooling ofthe surface electrode during treatment. This treatment approach can bepainful, and can lead to short-term swelling of the treated area. Also,because of the relatively large volume of tissue treated and the need tobalance application of RF current with surface cooling, this RF tissueremodeling approach does not permit fine control of damage patterns andsubsequent skin tightening. This type of RF technique is monopolar,relying on a remote grounding of the patient to complete the currentflow from the single electrode. The current in monopolar applicationsmust flow through the patient's body to the remote ground, which canlead to unwanted electrical stimulation of other parts of the body, incontrast, bipolar instruments conduct the current between two relativelynearby electrodes through a more localized pathway.

In view of the shortcomings of the above methods of dermatologicaltreatment and tissue remodeling, there is a need to provide a procedureand apparatus that combine safe and effective treatment for tissueremodeling, skin tightening, and wrinkle removal with minimal sideeffects, such as intra-procedural discomfort, post-proceduraldiscomfort, lengthy healing time, and post-procedural infection.

Citation or identification of any document in this application is not anadmission that such document is available as prior art to the presentinvention.

SUMMARY OF THE INVENTION

It is therefore one of the objects of the present invention to providean apparatus and method that combines safe and effective treatment foran improvement of dermatological disorders with minimum side effects.Another object of the present invention is to provide an apparatus andmethod that promotes skin tightening and wrinkle removal by creation ofa pattern of small localized regions of thermal damage within thedermis. Still another object of the present invention is to provide amethod and apparatus for skin tightening or other forms of tissueremodeling by using an array of electrode needles to controllablydeliver electrical or thermal energy to predetermined locations withinthe dermis or other tissue

These and other objects can be achieved with an exemplary embodiment ofthe apparatus and method according to the present invention, in whichportions of a target area of tissue are be subjected electromagneticradiation, such as radio frequency pulses, or thermal energy.Electromagnetic radiation is directed to portions of a target areawithin the skin or deeper tissue using minimally invasive methods,causing fractional wounding of the portions of the target area. Theelectromagnetic radiation may be generated by an electromagneticradiation source, which is configured to deliver heat, radio frequencypulses, electrical current, or the like to a plurality of target areas.

In yet another exemplary embodiment according to the present invention,an electromagnetic radiation source is configured to generateelectromagnetic radiation, and a delivery device comprising an array ofneedles, coupled to the electromagnetic radiation source, is configuredto penetrate the skin to a desired depth to deliver the electromagneticradiation directly to a plurality of target areas.

One method in accordance with the present invention comprises insertingan array of needles into a region of skin to a predetermined depth.Radio frequency pulses of electrical current are then applied to one ormore of the needles, which can function as electrodes in monopolar orbipolar modes to create regions of thermal damage and/or necrosis in thetissue surrounding the tips of the needles.

In an alternate aspect of the invention, one or more of the needles inthe array may be hollow and used to deliver small amounts of analgesicor anesthetic into the region of skin being treated. These hollowneedles may be interspersed among the electrode needles in the array,and they may also function as electrodes.

In another embodiment of the invention, the electrode needles may alsobe connected to a second source of electrical current in the milliampererange. Detection of a nerve close to any of the inserted needles of thearray is achieved by sequential application of small currents to theneedles in the array and observation of any visible motor response. If anerve is detected, the nearby needle or needles can be deactivatedduring the subsequent application of RF current to other electrodeneedles in the array to avoid damaging the nerve.

In yet another embodiment of the invention, the methods and apparatusdescribed herein can be used to heat portions of cartilage, such as thatlocated in the nose, using a minimally invasive technique, allowingreshaping of the pliant heated cartilage to a desired form.

A further understanding of the nature and advantages of the presentinvention will become apparent by reference to the remaining portions ofthe specification and drawings.

BRIEF DESCRIPTION OF THE DRAWINGS

The following detailed description, given by way of example, but notintended to limit the invention solely to the specific embodimentsdescribed, may best be understood in conjunction with the accompanyingdrawings, in which:

FIG. 1 is a schematic drawing of a cross section of a tissue treatedusing the ASR method.

FIG. 2 is a schematic drawing of a cross section of a tissue treatedusing the NSR method.

FIG. 3 is a schematic illustration of an apparatus for conducting tissuereshaping using electromagnetic energy according to one embodiment ofthe present invention.

FIG. 4 is a schematic illustration of portions of an apparatus forconducting tissue reshaping according to one embodiment of the presentinvention.

Throughout the drawings, the same reference numerals and characters,unless otherwise stated, are used to denote like features, elements,components, or portions of the illustrated embodiments. Moreover, whilethe present invention will now be described in detail with reference tothe Figures, it is done so in connection with the illustrativeembodiments and is not limited by the particular embodiments illustratedin the Figures.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to methods and apparatus for improvementof skin defects including, but not limited to, wrinkles, stretch marks,and cellulite. In one embodiment, skin tightening or tissue remodelingis accomplished by creating a distribution of regions of necrosis,fibrosis, or other damage in the tissue being treated. The tissue damageis achieved by delivering localized concentrations of electrical currentthat is converted into heat in the vicinity of the tips of the electrodeneedles. Inducing regions of local thermal damage within the dermisresults in an immediate shrinking of collagen, leading to beneficialskin tightening response. Additionally, the thermal damage tends tostimulate the formation of new collagen, which makes the local skintissue fuller and gradually leads to additional skin tightening andreduction of wrinkles.

In an exemplary embodiment of the present invention, tissue treatmentapparatus 300 shown in FIG. 3 may be used to create regions of damagewithin the tissue being treated. The tissue reshaping apparatus maycomprise a plurality of needles 350 attached to a base 310. The base isattached to housing 340 or formed as a part of the housing. A source ofRF current 320 is electrically connected to each of the needles 350. Acontrol module 330 permits variation of the characteristics of the RFelectrical current, which can be supplied individually to one or more ofthe needles. Optionally, energy source 320 and/or control module 330 maybe located outside of the housing.

In one exemplary embodiment, the energy source 320 is a radio frequency(RF) device capable of outputting signals having frequencies in adesired range in another exemplary embodiment, the energy source iscapable of outputting an AC or DC electric current. The control module330 provides application-specific settings to the energy source 320. Theenergy source 320 receives these settings, and generates a currentdirected to and from specified needles for selectable or predetermineddurations, intensities, and sequences based on these settings.

In yet another embodiment of the present invention, a spacer substrate315 containing a pattern of small holes through which the array ofneedles protrudes may optionally be provided between the base 310 andthe surface of the skin 306. This spacer substrate may be used toprovide mechanical stability to the needles. Optionally, this substratemay be movably attached to the base 310 or housing 340 and adjustablewith respect to base 310, supporting the array of needles to control thedepth of the needles protruding from the lower surface 316 of spacersubstrate 315, and thus controlling the depth to which the needles areinserted into the skin.

In practicing a method in accordance with the present invention, thesharp distal ends of needles 350 pierce the surface 306 of skin tissue305 and are inserted into the tissue until the bottom surface 316 ofspacer substrate 315 (or the bottom surface 311 of base 310 if a spacersubstrate 315 is not used) contacts the surface 306 of the skin 305.This configuration permits reliable insertion of the array of needles toa predetermined depth within the tissue being treated. Control module330 is then configured to deliver controlled amounts of RF current toone or more needles 350.

Base 310 and/or spacer substrate 315, if used, can be planar or they mayhave a bottom surface that is contoured to follow the shape of theregion of tissue being treated. This permits penetration of the needlearray to a uniform depth within the targeted tissue even if the surfaceof the skin is not planar, e.g., along the eye sockets.

In another embodiment, base 310 and/or a spacer substrate 315, if used,may be cooled by any suitable means (such as by embedded conduitscontaining circulating coolant or by a Peltier device) to cool thesurface of the skin when the needle array penetrates the skin to reduceor eliminate pain. The surface region of the skin being treated and/orthe needles themselves may also be precooled by separate means,including convective or conductive means, prior to penetration of theskin by the array of needles.

In a preferred embodiment of the present invention, the shafts ofconductive needles 350 are electrically insulated except for the portionof the needle near the tip. In the apparatus of FIG. 3, application ofRF current to the needles 350 causes heating in the exposed tip region,inducing thermal damage regions 370 around the tip of each needle.Thermal damage regions 370 result from operation of the apparatus inmonopolar configuration, in which a remote grounding electrode, notshown in FIG. 3, is attached to a remote part of the patient's body tocomplete the circuit of electricity conveyed to needles 350 by energysource 320. In this monopolar configuration, RF current causes heatingof the tip regions of the needles 350, generating thermal damage intissue regions 370 adjacent to the needle tips that are approximatelyspherical or slightly elongated in shape.

In one embodiment of the invention, current may be deliveredsimultaneously to all needles in the array to produce a pattern ofthermal damage around the tip of each needle. In alternativeembodiments, control module 330 and energy source 320 can be configuredto supply electrical current to individual needles, to specific groupsof needles within the array, or to any combination of individual needlesin any desired temporal sequence. Providing current to different needlesat different times during treatment (instead of heating all needles inthe array at once) may help to avoid potential local electrical orthermal interactions among needles that can lead to excessive localdamage.

In yet another embodiment of the present invention one or more vibratingmeans, such as a piezoelectric transducer or a small motor with aneccentric weight fixed to the shaft, may be mechanically coupled tohousing 340 and/or base 310 that supports the array of needles 350.Vibrations conductively induced in needles 350 by such vibrating meanscan facilitate the piercing of the skin by the needle tips andsubsequent insertion of the needles into the tissue. The vibrating meanscan have an amplitude of vibration in the range of about 50-500 μm or,more preferably, between about 100-200 μm. The frequency of the inducedvibrations can be from about 10 hz to about 10 khz, more preferably fromabout 500 hz to about 2 khz, and even more preferably about 1 khz. Theparticular vibration parameters chosen may depend on the size andmaterial of the needles, the number of needles in the array, and theaverage spacing of the needles. The vibrating means may further comprisean optional controller capable of adjusting the amplitude and/orfrequency of the vibrations.

Additional details and embodiments of the present invention are shown inFIG. 4. Conductive needles 410 and 415 are shown attached to base 310.Insulation 420 covers the shaft of needles 410 and 415 protruding frombase 310 except for the region near the lower tip, and electricallyinsulates each conductive needle shaft from surrounding tissue 305.Electrical conductors 430 and 431, which may be wires or the like,extend from an upper portion of needles 410 and 415 respectively, andare connected to the energy source (not shown here). Suitable insulatingmaterials for insulation 420 include, but are not limited to, Teflon®,polymers, glasses, and other nonconductive coatings. A particularmaterial may be chosen as an insulator to facilitate penetration andinsertion of needles 410 and 415 into tissue 305.

Needles 410 and 415 are shown operating in bipolar mode in anotherembodiment of the present invention. Needle 410 is a positive electrodedelivering RF of other current to the tip region of the needle from theenergy source via conductor 430. Needle 415 functions as a groundingelectrode that is connected to the ground of the energy source viaconductor 431. In this configuration the applied current will travelthrough the tissue between the tips of needles 410 and 415, generatingan elongated region of thermal damage 425 around and between the tips ofthe two needles.

An elongated region of damaged tissue 425 can be created between any twoadjacent or nearby needles in the array through proper configuration ofcontrol module 330 and energy source 320. In an embodiment of thepresent invention, elongated damage regions 425 are formed betweenseveral pairs of needles within the array of needles to form a desireddamage pattern in the tissue 305. The regions of thermal damage 325created in bipolar operation of the apparatus may be formedsimultaneously or, alternatively, sequentially, using any combinationsof proximate needles in the array to form each region. A wide variety ofthermal damage patterns can be created using a single array of needlesthrough appropriate configuration of energy source 320 and controlmodule 330 to deliver predetermined amounts of current between selectedpairs of needles. This apparatus thus allows for the creation of complexdamage patterns within the tissue 305 that may be macroscopicallyelongated in preferred directions to produce anisotropic shrinkage andreshaping.

In practicing the methods and apparatus of the present invention, theneedles can have a width of about 500-1000 μm or preferably about700-800 μm. Needles less than 500 μm in diameter may also be used ifthey are mechanically strong enough. Needles thicker than about 1000 μmin diameter may be undesirable because of the difficulty in forcinglarger needles to penetrate the skin and because of the increasedpropensity for pain and scarring. The length of the needles extendinginto the skin will depend on the targeted depth for damaging the tissue.A typical depth for targeting collagen in the dermis is about 1500-2000μm, although shallower or deeper distances may be preferred fordifferent treatments and regions of the body being treated. Needleswithin a single array may protrude by different lengths from the base310 or spacer substrate 315. This will cause the tips of the needles tobe positioned at different depths within the tissue being treated, andallow creation of damaged tissue at more than one depth. This variationin needle depth can achieve formation of damaged tissue over a largervolume within the tissue being treated.

The needle arrays may have any geometry appropriate for the desiredtreatment being performed. The spacing between adjacent needles ispreferably greater than about 1 mm apart, and may be as large as about 2cm. The spacing between needles in an array need not be uniform, and canbe closer in areas where a greater amount of damage or more precisecontrol of damage in the target area of tissue is desired. In oneembodiment, the array of needles may comprise pairs of needles separatedfrom adjacent pairs by larger distances. This geometry may bewell-suited for inducing damage in bipolar mode between pairs ofneedles. Needles may also be arranged in a regular or near-regularsquare or triangular array. In any array geometry, the pattern of damageand resultant tissue reshaping may be controlled with some precision byadjusting the intensity and duration of power transmitted to singleneedles or pairs of needles.

The amount of energy directed to a given needle will vary depending onthe tissue being treated and the desired extent of thermal damage toinduce. For typical needle spacings noted above, the energy sourceshould be configured to deliver about 1-100 mJ per needle or pair ofneedles in the array. It may be preferable to initially use loweramounts of energy and perform two or more treatments over the sametarget area to better control the damage patterns and extent ofreshaping.

In yet another embodiment of the present invention, one or more of theneedles in the array may be hollow, such as needle 440 in FIG. 4. Centerchannel 450 may be used to deliver a local analgesic such as lidocaine2% solution from a source (not shown) located within or above base 310into the tissue 305 to reduce or eliminate pain caused by the thermaldamage process.

In yet another embodiment of the present invention, hollow needle 440 isbifunctional, capable of conducting RF current or other energy viaconductor 432 and also capable of delivering a local analgesic or thelike through center channel 450. Similar to needles 410 and 415,bifunctional needle 440 has insulation 445 covering the shaft extendingfrom base 310 except for the region near the lower tip. Analgesic may besupplied to the tissue either before or during application of RF orother current to the needle 450.

In one embodiment of the invention, one or more of the needles in thearray may be bifunctional like needle 440. Alternatively, one or moreneedles may be hollow and optionally nonconductive, suitable only fordelivering a local analgesic or the like. The array of needles used fora given application may comprise any combination of solid electrodes,bifunctional needles, or hollow nonconductive needles. For example, onetype of needle array may comprise pairs of electrode needles operatingin bipolar mode, with a hollow needle located between each pair. In thisconfiguration, the hollow needle can deliver analgesic to the tissuebetween the tips of the electrode needles prior to applying current tothe electrodes and causing thermal damage in the numbed tissue.

In yet another embodiment of the present invention, one or more of theneedles in the array may be further connected to an electronic detectionapparatus and perform the additional function of a probe to detect thepresence of a nerve near the tip. The electronic detection apparatus maycomprise a source of electrical current in the milliampere range andcontrol means to send small currents on the order of a milliamp tospecific needles in the array. Detection of a nerve close to any of theinserted needles of the array is performed by sequential application ofsmall currents to the needles in the array and observation of anyvisible motor response. If a nerve is detected, control module 330 canbe configured to deactivate the needle or needles close to the nerveduring the subsequent treatment to avoid damaging the nerve. A nervedetection method based on principles similar to those described hereinis disclosed by Urmey et al. in Regional Anesthesia and Pain Medicine27:3 (May-June) 2002, pp. 261-267.

In still another embodiment, one or more of the needles may be hollow,and a light fiber or light guide is inserted into the hollow needle suchthat one end of it extends to or slightly protrudes from the needle tip.The other end of the light fiber or light guide in communication with asource of optical energy. Optical energy supplied to the tip of thelight guide or light fiber may then be used to heat the tip, which thenheats the surrounding tissue, i.e., the target area, to cause fractionalwounding at the needle tip. An array of needles used in accordance withthe present invention may comprise a mix of electrode needles andlight-guide needles. Alternatively, each needle may carry a light guideand all of the energy used to cause thermal damage may be generated bythe optical energy source instead of using RF or other electricalcurrent. A portion of the light guide or light fiber, such as theportion at the tip of the needle, may be configured to absorb energy andfacilitate conversion of the optical energy to heat. In theseembodiments, the optical energy source may comprise, but is not limitedto, a diode laser, a diode-pumped solid state laser, an Er:YAG laser, aNd:YAG laser, an argon-ion laser, a He—Ne laser, a carbon dioxide laser,an eximer laser, or a ruby laser. The optical energy conveyed by a lightguide or light fiber may optionally be continuous or pulsed.

Treatments performed in accordance with the present invention may beused to target collagen in the dermis. This can lead to immediatetightening of the skin and reduction of wrinkles overlying the damagedtissue arising from contraction of the heated collagen. Over time, thethermal damage also promotes the formation of new collagen, which servesto smooth out the skin even more.

An alternative application of the methods of the present invention maybe to reduce or eliminate the appearance of cellulite. To achieve this,the arrays of needles are configured to target the dermis and optionallythe upper layer of subcutaneous fat directly. Creating dispersedpatterns of small thermally-damaged regions in these layers can tightenthe networked collagen structure and suppress the protrusion of thesubcutaneous fat into the dermal tissue that causes cellulite.

Yet another application of the methods and apparatus of the presentinvention is to reshape cartilage. It is known that cartilage softensupon heating, and heating it to about 70 degrees C. can soften thecartilage sufficiently to permit reshaping that persists upon cooling.Currently, specialized lasers are used to heat and soften cartilage inthe nasal passages for reshaping. Using the methods and apparatusdescribed herein, cartilage can be targeted by art array of needles andheated in a suitably gradual way, using lower power densities and longertimes, to provide relatively uniform heating. Shaping of the cartilageis thus possible using a minimally invasive technique that can be usedwhere laser heating may not be feasible.

Any of the thermal damaging and tissue reshaping methods practiced inaccordance with the present invention may be performed in a singletreatment, or by multiple treatments performed either consecutivelyduring one session or at longer intervals over multiple sessions.Individual or multiple treatments of a given region of tissue can beused to achieve the appropriate thermal damage and desired cosmeticeffects.

What is claimed is:
 1. A skin treatment method comprising: inserting aplurality of needles through a dermal layer of skin and into asubcutaneous fat layer, the plurality of needles being attached to abase, the plurality of needles being further configured to receive radiofrequency (RF) energy from a RF energy source; and regulating deliveryof the RF energy from the RF energy source to the plurality of needlesto induce thermal damage by the RF energy in the subcutaneous fat layerwhen the needles are inserted therein, wherein the regulating of thedelivery of the RF energy is configured to cause a pattern of fractionalthermal damage having thermally damaged regions in the subcutaneous fatlayer.
 2. The method of claim 1, wherein the plurality of needles areassociated with each other in groups of bipolar pairs, whereinregulating the delivery of the RF energy includes controlling the RFenergy being delivered to bipolar pairs to cause areas of non-ablativedamage within the subcutaneous fat layer, and wherein each area ofnon-ablative damage is associated with each bipolar pair of theplurality of needles.
 3. The method of claim 1, wherein at least one ofthe plurality of needles is a mono-polar needle.
 4. The method of claim1, further comprising selecting an application-specific setting for theenergy source to cause the energy source to vary at least one of aduration, intensity, and sequence of the RF energy transmitted to theplurality of needles based on the selected setting.
 5. The method ofclaim 1, wherein at least two of the plurality of needles have differinglengths.
 6. The method of claim 1, further comprising cooling a surfaceof the skin when inserting the plurality of needles through the dermallayer of skin.
 7. The method of claim 1, wherein at least one of theplurality of needles is a hollow needle, and further comprisingdelivering an analgesic via the hollow needle to tissue surrounding atip of the hollow needle.
 8. The method of claim 1, further comprisingdetecting, using a detector, a presence of a nerve near a tip of atleast one of the plurality of needles.
 9. The method of claim 1, whereininserting the plurality of needles through the dermal layer of skin andinto the subcutaneous fat layer comprises passing the plurality ofneedles through a plurality of holes formed in a spacer disposed betweenthe base and a surface of the dermal layer of skin, wherein theplurality of needles are movable relative to the spacer.
 10. The methodof claim 1, wherein regulating delivery of RF energy further includesinducing damaged regions surrounding each tip of each of the pluralityof needles, with undamaged regions between the damaged regions.
 11. Themethod of claim 1, wherein each of the needles has a tip, wherein thepattern of thermally-damaged regions includes at least two adjacentregions of thermal damage, and wherein each adjacent region of thermaldamage includes a small localized area of thermal damage surroundingeach tip.
 12. A skin treatment method, comprising: inserting a pluralityof needles through a dermal layer of skin and into a subcutaneous fatlayer, the plurality of needles being attached to a base, the pluralityof needles being further configured to receive radio frequency (RF)energy from a RF energy source; and regulating delivery of the RF energyfrom the RF energy source to the plurality of needles to induce thermaldamage in subcutaneous fat layer in a vicinity of the tips of theneedles, wherein regulating the delivery of the RF energy is controlledto cause a pattern of fractional damage having thermally-damaged regionswithin the subcutaneous layer, and wherein at least two adjacentthermally-damaged regions have an undamaged region therebetween.
 13. Themethod of claim 12, wherein the thermally-damaged regions includenecrosis.
 14. The method of claim 12, wherein inserted and regulatingalso result in thermal damage in the dermal layer.
 15. A skin treatmentmethod comprising: inserting a plurality of needles through a dermallayer of skin and into a subcutaneous fat layer, the plurality ofneedles being attached to a base and arranged in a group of bipolarpairs, the plurality of needles being further configured to receiveradio frequency (RF) energy from a RF energy source; and regulatingdelivery of the RF energy from the RF energy source to the plurality ofneedles to induce a pattern of fractional damage by the RF energy in thesubcutaneous fat layer when the needles are inserted therein, whereinthe pattern of fractional damage includes thermally-damaged regionsbetween tips of needles of the bipolar pairs, and undamaged regionsbetween bipolar pairs of needles in the group.
 16. The method of claim15, wherein the thermally-damaged regions are elongated between theneedles of the bipolar pairs.
 17. The method of claim 15, wherein thethermally-damaged regions include necrosis.
 18. A skin treatment methodcomprising: inserting a plurality of monopolar needles through a dermallayer of skin and into subcutaneous fat layer, the plurality ofmonopolar needles being attached to a base and configured to receiveradio frequency (RF) energy from a RF energy source; and regulatingdelivery of the RF energy from the RF energy source to the plurality ofneedles to induce a pattern of fractional damage by the RF energy in thesubcutaneous fat layer when the needles are inserted therein, whereinthe pattern of fractional damage includes thermally-damaged regions in avicinity of each tip of each of the plurality of monopolar needles, andundamaged regions between the damaged regions.
 19. The method of claim18, wherein the thermally-damaged regions include necrosis.